Power chisel



K. H. OLESON Nov. 24, 1964 POWER CHISEL 2 Sheets-Sheet l Filed Nov. l5, 1962 @Uf slhlllllll/ll INVENTOR. ANNETHH. 0L EsoN Nov. 24, 1964 K. H. oLEsoN 3,157,947

POWER CHISEL Filed Nov. l5, 1962 2 Sheets-Sheet 2 kga INVENTOR. KENNETH h. 0L E60/v ATToR/wsrr United States Patent O ice 3,157,947 POWER CHISEI, Kenneth H. Giesen, tltl Superior St., Storm Lahe, iowa Filed Nov. i3, i962, Ser. No. 236,9l6 Claims. (Cl. Sil- 273) This invention is a power cocked and triggered spring vdriven chisel which has several advantages over reciproeating chisel structures previously proposed. It is novel in that it uses a double cycloid arrangement to compress or cock and also trigger or release the spring so that the spring may drive the chisel in cutting action. The device is novel in that it uses the cycloid structure only to actuate the spring rather than to drive the chisel in reciprocating motion. The device also incorporates a novel shoe or guide which allows a great variety of chiseling work to be done.

Accordingly, it is a principal object of this invention -to provide a novel power chisel.

it is a further object of this invention to provide a novel power chisel in which cutting power is provided by a spring.

lt is a further object of this invention to provide a novel chisel in which the user is protected to some extent from the jars involved in reciprocating tools.

It is a further object of this invention to provide a power driven tool in wln'ch the power source merely cocks and triggers a compression spring.

It is yet a further object of this invention to provide a reciprocating chisel structure in which the depth to which the chisel cuts can be accurately controlled.

It is a further object of this invention to provide a power chisel in which the angle at which the chisel structure approaches the surface to be cut can be altered, through a wide range of angles.

It is a still further object of this invention to provide a power chisel construction that may be made light so as to be highly maneuverable and is adapted also to heavy structure for heavy duty, industrial and professional use.

Other and further objects of the invention are those inherent and apparent in the apparatus as described, pictured and claimed.

To the accomplishment of the foregoing and related ends, this invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.

The invention will be described with reference to the drawings in which corresponding numerals refer to the same parts and in which:

FIGURE 1 is a side elevation of the device with portions broken away to illustrate internal construction and with hidden portions and adjusted positions illustrated in broken lines;

FIGURE 2 is a partial vertical section taken on the line 2-2 of FIGURE l; broken lines show hidden parts;

FIGURE 3 is an additional vertical section taken on the line and in the direction of the arrows 3 3; hidden parts are illustrated by broken lines;

FIGURE 4 is a View similar to FIGURE 3 except that the structure is shown in lan adjusted position;

FIGURE 5 is a horizontal section taken on the line and in the direction of the arrows 5 5; and

FIGURE 6 is a special form of blade adapted to removing glazing materials from window sash Containing glass.

Referring to the drawings, the device is seen in FIG- URE l as being powered by a conventional electric motor Patented Nov. 24, i964- itl mounted in any suitable housing l1 and provided with a suitable hand grip l2 by means of which the operator can maneuver it. A fragment of a conventional cord ,ld is shown which provides a means for bringing electrical energy to motor lil. 0n the handle l2, at a convenient location, a suitable switch l5 is provided which controls the flow of current to motor 10. Handle l2 may be formed integrally, although not necessarily so, with the front housing portion 16 winch provides a suitable support for the reciprocating cutting structure which will be described in more detail below. In between housing portion 316 and housing portion ll is a gear box housing portion i7'.

The shaft lil of motor lll extends into gear box housing i7 and carries on its forward end a suitable spur gear 1?. This in turn meshes with a gear Ztl which is separately supported in a rotatable position on its own shaft within the gear box. Actually, there are two gears, such as the one Ztl which may be seen by reference to FIG- URE 2, 2@ being on the right and a substantially identical gear 2l on the left; Also, still with reference to FIG- URE 2, the gear 19 will be seen to mesh with only gear 2t). Gear Ztl and gear 2l. are in mesh with each other, however, so that driving gear Ztl effectively drives both the gears. v

Referring again to FIGURE l and this time to the portion of the housing designated 16, we see a suitable bearing 22 within which is slidably mounted a shaft 24. A suitable compression spring 25 engages the top of shaft 24 and also embraces a boss 2d at its upper end which holds it in position over the top of shaft 2d. While illustratively the spring has been shown as a compression spring, it is entirely possible to spring load the shaft 2li other ways, this one simply being extremely direct and rsimple and therefore illustrated and described as the preferred form. Y

A lifting plate 27 is secured to shaft 24 in any suitable manner here shown by means of a cap screw 28. The lifting plate is engaged by the cycloid plate followers, one of which 29 may be seen in FIGURE 1 mounted on a shaft 30 which is supported on the gear Ztl. Turning momentarily to FIGURE 2, a similar plate follower 3l is supported on a shaft 32, on gear 21.

Returning to FIGURE 1, at the lower end of shaft 24 is a suitable chuck arrangement 34 here shown as one provided with four clamping means 35 in the form of set screws or the like to secure the blade against both vertical and lateral displacement during the chiseling operation. The chisel blade itself appears at 3o.

To aid in controlling the chisel blade accurately on a work piece, a foot member 37 is provided which is supported by the bracket 38 and clamped in position suitably as by the butterfly nut and bolt assembly 39. The butterfly nut and bolt assembly extends through a slot do in the leg il that is part of housing 17 so that by loosening the butterfly nut and bolt assembly l 39 the foot may be raised and lowered. In FIGURE l,

it is shown in a raised position providing maximum chisel depth. When it is lowered to its lowest most position, chisel blade 35 barelyiengages a surface toward which a chisel blade is driven by spring 3S. Foot 37 may be also pivoted about the butterfly nut and bolt assembly 39 and a calibrated dial plate 42 is provided that may slide vertically with the rest of the unit but is held against rotation suitably as by having a tongue member 44 that engages in a slot 4S in leg il shown clearly in FIGURE 2. In FEGURE 2 also the lift plate 27 appears in lowered position.

At the left of FIGURE l, which is the front of housing portion 16, is a second foot member 50 which is pivotally supported on housing 1o as seen at 51. Slotted o braces such as the one 52 are pivoted to the foot 5t? as at 54 and are clamped in various adjusted positions by some suitable means such as the butterfly nut S. As shown in broken lines in that figure, the foot 5t? may be set within a range of angles different from that for foot 37. The angle at which foot 5t) is set may be a very low one, less than degrees say, with respect to the line of motion of shaft 24. By putting an appropriate chisel in chuck 3d, a stroke may be made at a very low angle with respect to the surface represented by the irregularly broken line 56, for example. It may be necessary to have a longer chisel blade than the one 36 and this is represented in broken lines by the chisel blade 36. By resting the device on the foot 50 and using a very broad faced or spade-like chisel structure a machine made according to the teachings of this invention can be extremely useful in shaving paint, for example, or other finishes from the surface on which they are. The angle at which the blade approaches the surface is so low, as low as l0 degrees perhaps, and the control of the machine is so good by reason of resting the machine on the foot Sil, that substantially no gouging of the surface is caused.

In FIGURE 3, plate followers 29 and 31 may be seen just engaging the biased edges of lift plate 27. Spring is fully extended and blade 36 is at its maximum down stroke. Ways 46 and 47 stabilize the lift plate 27 against rotational or pivoting movement while leaving it free to slide up and down.

In FIGURE 4 the followers 29 and 31 have carried the plate to its maximum upward stroke. Spring 25 is fully compressed and chisel 36 has been lifted to its maximum level. Any additional rotation of the gears Ztl and 21 will cause the respective followers 29 and 31 to move outside the path of lift plate 27 and as a result spring 2S will extend suddenly and drive the shaft 24 carrying the chisel member 36 downward to deliver a working stroke. In FIGURES 3 and 4, it may be seen that foot 37 is provided with an edge 33 which may be manipulated as to provide an edge aligning exactly with the edge of blade 36 for guiding the blade close to an object to be chiseled.

While it is illustrated and shown here as a lightweight utility device as for the home craftsman or the like, or for light industrial work, obviously the structure lends itself to being made in a heavy duty industrial form for heavy duty work.

When motor 1t) is turned on by means of switch 15 with cable 14 connected to a source of electrical energy, spur gear 19 is rotated rapidly. This gear rotates in a counterclockwise direction when viewed in FIGURE 2 which causes gear 2i) to rotate in a clockwise direction carrying the follower 29 toward the outside of the case at the top and toward the inside of the case at the bottom. This movement brings follower 29 up under the lift plate 27 and as the lift plate followers 29 and 31 are identically located on their respective gears, they engage the two ends of the lift plate 27 simultaneously. This action of course forces the shaft 24 to be lifted as shown in FIGURE 4.

As these gears continue to rotate under the influence of motor .1.0, the followers move out of the path of lift plate 27 and spring 25 drives plate 36 suddenly downward to the position shown in FIGURE 3. The cutting action is, however, entirely spring driven, and the action is entirely dependent on the energy stored in the spring and the inertia generated in the shaft 24. When this has been dissipated as by striking an object, even if the blade has not extended to its full depth as shown in FIGURE 3, the blade stops without transmitting any undue shock to the operator holding the machine by handle 12. This is contrary to the experience of operators using directly driven reciprocating units as whore a crank or other mechanical means is positively linked to the cutting mechanism so that the working tool is is both lifted and driven downwardly positively. For this reason a relatively steady control is maintained over the chisel when it is cutting. Furthermore, the operator experiences much less fatigue in that there is a minimal amount of shock transmitted back via handle 12. The operator can set the adjustable foot to make a reasonable depth of cut on the material being worked on which assists in retaining good control over the machine.

FIGURE 6 illustrates a special form of chisel adapted particularly to removing glazing from a window sash in which the window light remains, at least partially. It is difficult to remove glazing compounds from window sash in which the light is retained in whole or in part using hand tools and avoid damaging the window light. If the window light is already broken, of course, the concern is not for the glass but to avoid possible danger to the operator from flying fragments. With a chisel blade such as that shown in FIGURE 6, however, glazing material can be removed from a window sash without the slightest danger of breaking the glass. The special blade in FIG- URE 6 has a shank 56 which is twisted as at 57 in relation to the blade portion 58. Cutting edge 59 therefore extends at right angles to shank portion 56. At one side of the blade portion 59 is a hook 60. As the blade 58 removes the glazing, hook 60 (if the device is held so as to place the hook adjacent the glass) extracts all glazer`s points from the sash.

The device is also safer in that the spring will allow the shaft to stop with the spring still partially compressed if the chisel hits some unresisting object. With the positively driven units, where there is no yield within the struc ture, it is possible the blade member 26 may be shattered and splinters of the broken blade sent flying. If the blade is directed against unyielding material while the case is held against movement away from the material, something must give. A spring driven blade can absorb such impacts with perhaps only -a dulled cutting edge as the damage resulting.

Among the chores which a tool of the type disclosed herein can perform well are the following: removing putty or other glazing material from window sash, preparing a brick surface for painting as by removing cracked or peeling plaster or stucco, shaving old paint from alsurface, preparing a masonry wall for painting `or cutting channels yas for electrical conduit.

It is apparent that many modifications and variations of this invention as hereinbefore set forth may be made without departing from the spirit and scope thereof. The specific embodiments described are given by way of example only and the invention is limited only by the terms of the `appended claims.

What is claimed is:

1. A reciprocating tool structure comprising a frame, a rotary power means secured to said frame, a rotatable drive member secured to and supported by said rotary power means, a pair of spaced apart rotatable elements connected in driving engagement with the rotatable drive member for rotation in opposite directions on parallel axes on said frame adjacent the drive member, a shaft slidably mounted in said frame adjacent to said rotatable elements, a lift plate secured to said shaft, a pair of followers, one such followers being secured to each of said rotatable elements and both followers engaging said lift plate in the portion of .the circular path of said followers when said followers rotate in an upward direction, a spring secured to said shaft and said frame to apply spring tension to said shaft in a. downward direction, said rotary power means rotating said drive member whereby both of said rotatable elements carry said followers on a path commencing below said lift plate and engaging it from the underside, lifting it for a time and then releasing .it as said followers move beyond the end of said lift plate, said shaft including a portion extending beyond said frame and means for securing a cutting tool to the portion of said shaft projecting beyond said frame.

2. A reciprocating cutting tool comprising a case, a rotary .power source in said case, a pair of gears mounted in said case and positioned near said rotary power source, said gears intermeshing with each other, a pinion gear secured to said rotary power source and engaging one of said pair of gears, follower members secured to said pai-r of gears and projecting therefrom, -a shaft slidably mounted in said case in front of said gears, a lift plate secured to said shaft and extending toward said gears and into the path of said followers, a boss means formed on the inside of said case directly above said shaft, a compression spring positioned between the top of said shaft and said boss, a portion of said shaft projecting outside of said case, a clamping chuck secured to the projecting end 0f said shaft and a cutting -tool removably secured to said chuck, said lift plate being narrower than the maximum distance between said follower members and Wider than the minimum distance between said cam followers as said gears rotate and said cam followers are carried on a circular pat-h thereby.

3. In a reciprocating tool, a case, a rotary power means mounted in said case, a handle secured to said case above said rotary power means, control means in said handle and connected to said rotary power means, Ia pair of gears rotatably secured to said case in front of said rotary power source, a shaft extending `from said rotary power source adjacent the edge of one of said gears, a pinion gear secured -to said nota-ry power source shaft and engaged with one of said gears, said gears being engaged with each other, pins carried by said gears, followers rotatably mounted on said pins, a shaft slidably mounted in said case and extending therebeyond, a boss formed in the inside of said case above said shaft, Ia compression spring trapped between said case 'and said shaft and held in position by said boss, a lift plate secured to the side of said shaft facing said gears, said lift plate being substantially narrower-,than the maximum distance between said followers attained when said gears are rotated so as to place said followers at the outside edges of said gears, said lift plate being substantially wider than the distance between said followers when said gears are rotated as to bring said followers adjacent 'to each other at the center of said case, the ends of said lift plate being biased, a chuck means secured to the ends of said shaft, said chuck means provided with multiple clamping members, a cutting blade secured to said chuck, a leg extending below said case at the rear of said shaft and a guide foot secured to said leg.

4. ll'lhe structure of claim 3 in which said guide foot is secured to the leg pivotally and vertically slidably, and means engaging said guide foot and said leg for rendering them immovable relative to each other.

5. The structure of claim 2 in which said cutting tool has a hook formed at one end of the cutting tool edge, said hook facing away from the cutting edge of said cutting tool.

References Cited in the ile of this patent UNITED STATES PATENTS 472,444 Fish Apr. 5, 1892 929,194 Compton July 27, 1909 972,225 Pennel Oct. 11, 1910 1,898,956 Harvie Feb. 21, 1933 2,015,535 Sacrey Sept. 24, 1935 2,085,462 Ewing June 29, 1937 2,220,223 Eerhard et al Nov. 5, 1940 2,295,186 Schwarzmayr Sept. 8, 1942 2,320,784 Livingston et al June l, 1943 2,869,824 Hazak Jan. 20, 1959 2,984,005 Evich May 16, 1961 

1. A RECIPROCATING TOOL STRUCTURE COMPRISING A FRAME, A ROTARY POWER MEANS SECURED TO SAID FRAME, A ROTATABLE DRIVE MEMBER SECURED TO AND SUPPORTED BY SAID ROTARY POWER MEANS, A PAIR OF SPACED APART ROTATABLE ELEMENTS CONNECTED IN DRIVING ENGAGEMENT WITH THE ROTATABLE DRIVE MEMBER FOR ROTATION IN OPPOSITE DIRECTIONS ON PARALLEL AXES ON SAID FRAME ADJACENT THE DRIVE MEMBER, A SHAFT SLIDABLY MOUNTED IN SAID FRAME ADJACENT TO SAID ROTATABLE ELEMENTS, A LIFT PLATE SECURED TO SAID SHAFT, A PAIR OF FOLLOWERS, ONE SUCH FOLLOWERS BEING SECURED TO EACH OF SAID ROTATABLE ELEMENTS AND BOTH FOLLOWERS ENGAGING SAID LIFT PLATE IN THE PORTION OF THE CIRCULAR PATH OF SAID FOLLOWERS WHEN SAID FOLLOWERS ROTATE IN AN UPWARD DIRECTION, 